Motor-operated circuit breaker



Jan. 29, 1946. o. JENSEN MOTOR-OPERATED CIRCUIT BREAKER o'riginalyiled Aug. 12, 1941 4 Sheets-Sheet l Jan. 29, 1946. o. JENSEN 2,393,688

MOTOR-OPERATED CIRCUIT BREAKER Original Filed Aug. 12, 1941 4 Sheets-Sheet 2 Jan. 29, 1946.

o. JENSEN 2,393,688Y

MOTOR-OPERATED CIRCUIT BREAKER Original Filed Aug. l2, 1941 4 Sheets-Sheet 3 Jan. 29, 1946. o. JENSEN MOTOR-OPERATED CIRCUIT BREAKER Original Filed Aug. l2, 1941 4 Sheets-Sheet 4 NWN,

Patented Jan. 29, 1946 2,393,6ss Moron-OPERATED CIRCUIT BREAKEB Otto Jensen, Malvern, Pa., assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Original application August 12, 1941, Serial No.

9 Claims.

My invention relates in general to electrical protective equipment and more particularly concerns a novel high-speed multi-pole circuit breaker and an electrical control system therefor. This invention is a division f my co-pending application Ser. No. 406,461, filed August 12, 1941, entitled Motor-operated circuit breaker.

The present invention involves the use of electrical protective equipment particularly adaptable to mercury arc rectifier circuits and is in the nature of an improvement over the copending application Serial No. 373,051, of Scott, llled January 3, 1941.

Generally, as described in the aforementioned application, the protection of mercury arc rectier circuits requires the adaptation of the protective equipment to single phase faults. Thus, in a polyphase mercury arc rectifier system, an electronic fault such as a back nre may cause extremely high values of current in the faulty anode circuit while the increase of current in the other phases will be relatively small.

It is obvious from mechanical principles that a single pole circuit breaker may be caused t0 open its contacts in less time than a multipole circuit breaker in which all the operating contacts are rigidly connected. Thus in the instance of the fault described for a mercury arc rectiiler,

it is particularly desirable in order to prevent excessive damage to the rectier and the circuit to open a set of contacts in the faulty anode circuit in as short a 'time as possible after the inception of the fault and to cause the contacts in the other anode circuits to open immediately thereafter.

In the aforementioned patent application, a multipole circuit breaker was disclosed for particular application to mercuryarc rectifier circuits. This circuit breaker consisted of a group of single pole interrupters, each independently responsive to fault current and each in a different phase of the power transformer feeding rectifier anodes. This group of interrupters was mounted upon a common frame and provided with pneumatic and mechanical operating mechanisms.

Thus the poles of the circuit breaker described could all be simultaneously closed and simultaneously opened. If a fault occurred in any particular anode circuit, its pole would immediately open its contacts and energize control means to cause the subsequent opening of the unaffected circuit breaker poles.

In the present application, the circuit breaker elements including the contacts, the are quencher Divided and this application July 31, 1942, Serial No. 453,010

and the tripping unit are in all respects the same as in the above named application, Serial No. 373,051. However, the control system has been altered so that a motor may be utilized to cause the opening and closing of the circuit breaker contacts. l

Thus the individual circuit breaker poles comprise a xed contact and a complementary movable contact which is carried upon a pivoted arm. This'arm may be rotated by a. cam which is driven by an electric motor. The operating cam is driven progressively in one direction and during one part of a revolution causes the closing of the circuit lbreaker contacts, and during another part of the revolution causes the opening of the circuit breaker contacts.

As in the earlier design, the movable contacts of the individual poles are provided with an automatic current responsive device which is operative to cause contact separation under the iniluence 'of springs independently of the position oi the contact operating cam.

An electrical interlocking control circuit, utllizing control switches the contacts of which are closed and opened in accordance with the movement of the operating cams and each movable contact, is utilized to cause the opening of all circuit breaker poles immediately after the automatic operation of any one pole.

The electrical control system is provided with relays to prevent repeated closing upon a fault,

with switching means to prevent closing when any of the rectifier auxiliaries are not in proper operation, and control switches which cause circuit breaker tripping when faults occur in the auxiliaries while the rectifier is in operation.

Accordingly, it is an object of the present invention to provide a novel high speed automatic circuit interruptor.

Another object oi my invention is to provide a multipole circuit breaker the poles of which are independently fault responsive and particularly adaptable to the protection of the anode circuits of mercury arc rectiilers.

Still another object of my invention is to provide a multipole circuit breaker having an electric motor for closing all of' the circuit breaker contacts simultaneously and for opening all of the circuit breaker contacts simultaneously.

A further object of my invention is to provide a. high speed multipole anode circuit breaker having a driving cam for each pole eective during a fraction of a revolution to cause closing of the circuit breaker contacts and eiective during another fraction of a revolution to cause opening of the contacts.

It is still a further object of my invention to provide a high speed circuit breaker particularly adaptable to the control of mercury arc rectiiier circuits having a plurality of coupled cams, one for each pole for closing or opening the circuit breaker contacts and automatic means for each pole to open the contacts independently of the cam position.

Another object of my invention is to provide a mercury arc rectiiier protective system including a circuit interrupter in each ,anode phase thereof and a control system for these anode breakers operative to cause tripping of all poles when a single pole has been automatically operated.

- These and other objects of my invention will now become apparent from the following specincation taken in connection with the accompanying drawings in which:

Figure 1 is a side view of a six-pole circuit breaker illustrating the manner in which individual poles are assembled upon a common frame.

Figure 2 is a fragmentary cross-sectional view of the contact operating shaft and illustrates the manner in which the contact operating cams are mounted and the manner in which the shaft is journalled.

Figure 2a is a side view of a contact operating cam.

Figure 3 is an end cross-sectional view of one oi.' the circuit breaker poles mounted upon the frame as illustrated in Figure 1.

Figure 4 is a fragmentary cross-sectional view of the circuit breaker pole illustrated in Figure 3 and illustrating the contacts in the opening circuit position immediately after automatic tripping.

Figure 5 is a fragmentary cross-sectional view corresponding to Figure 4 and illustrates the contacts in a position for reclosing.

Figure 6 is a schematic diagram of the multipole circuit breaker control system.

The individual circuit breaker poles are in most respects similar to those described in the aforementioned application. In Figure 1 the individual circuit breaker poles 2| are shown assembled into a single multipole unit upon a. structural steel frame 22.

The six-poles illustrated are similar to each other and may be readily assembled upon the frame 22 and removed therefrom for servicing.

As illustrated in Figure 3, the structural steel frame 22 comprises the channels 23 and 24 which are spaced by suitable cross members at each end of the frame.

Each of the individual circuit breaker poles 2| is assembled in two distinct sections and secured to a pair of cross bars 25 as illustrated in Figures 1 and 3. These cross bars 25 are metallic members encased in a layer of insulation to isolate the two sections from each other and from the frame. The cross bars are secured to the channels 23 and 24 by a pair of clamping members 26 and 21 which as illustrated in Figure 1 bear down upon the ends of the cross bars 25. These clamps are held in position by the screws 3| and the lock washers 32. Locating plates 33 are welded to the frame and assure the proper spacing of the individual poles alongthe supporting channels 23 and 24.

Near one end of the cross bars 25, a plurality of clamping members 34 and screws 36 secure a plate 36 thereto. Secured to the plate I6 by a plurality of screws 31 is a conductive coil 4| which includes an integral extension 42 to which a conductor 43 may be readily secured. An oppositely disposed extension 44 provides a mount to which a stationary contact 45 may be secured as illustrated in Figures 3, 4 and 5.

An arc quencher 46 is pivotally supported upon a pin 41 which is carried by a bearing member 6| secured to the extension 42 of the coil 4|. Thus the arc quencher 46 may be rotated from the position illustrated in Figure 3 about its pivot 41 to expose the contact structures and thus facilitate cleaning and replacement.

The particular nature of the arc quencher bears no relation to the present invention. A brief description of certain parts, however, may aid the reader in understanding the drawings. As illustrated, the coil 4| surrounds va laminated magnetic member 52, the extensions 55 of which embrace the arc quencher 46 as illustrated in Figure 1.

Thus the magnetic members 53 are disposed on opposite sides of the arc quenchers 46 and accordingly a transverse magnetic eld is established which during circuit interruption will tend to drive an arc up into the chute 46.

'I'he extension 13 of the main circuit breaker supporting frame carries a stud 15 and cooperating nuts 16 which secure a lug 11 extending from the arc quencher structure 46. Thus to rotate the arc quencher about its pivot 41 the upper nut 16 must rst be removed from stud 15.

The operating elements of this circuit interrupter are carried in a U-shaped frame 54 which is secured to the cross bars 25 by suitable clamping members as is more completely illustrated and described in the copending application. The walls of the U-shaped frame 54 are suitably drilled to carry a shaft 65 upon which a contact operating arm 56 is pivoted.

The contact arm 56 carries at its upper end a pin 51 upon which a contact carrying member 6| is rotatably supported and biased in a clockwise direction by compression spring 62. The compression spring 62 is retained between the contact carrying member 6| and an integral extension 63 of the contact carrying arm. The movable contact 64 is secured to the contact carrying member 6| by a plurality of screws 65 and accordingly contact 64 is normally biased by compression spring 62 towards the stationary contact 45. The movement caused by this bias is limited by the engagement of the extension 66, of the member 6|, with web 63 of the contact arm.

Current is led to the movable contact 64 from a line conductor 66 through automatic trip coil 61 and through a flexible conductor 1| to an extension 66 of the contact carrying member 6|.

The tripping coil 61 may comprise as illustrated a single turn of relatively heavy copper bar and the line conductor 66 and the flexible conductor 1| may be attached thereto by suitable bolts. Hence it may be seen that when the circuit breaker contacts are in the position illustrated in Figure 3, a circuit is completed from conductor 66 through the engaged contacts 64 and 44 to the line conductor 43.

The movable contact 64 is normally biased towards the open circuit position by a tension spring 12 which is secured to an extension 15 of the U-shaped frame. The force of spring 12 is transmitted to the contact 64 through pin 51 to which the spring is attached at one end while the other end of the spring is pivotally anchored to the extension 13 of the'U-shaped frame by the pin 14. i l

' An actuating arm 6| pivoted about the pin 55 controls the movement of the contact arm 56. The arm 8| comprises a main body section and an extension 82 which is drilled at 83 to carry a pin 84. Rotatably mounted upon thispin is a roller 85 which cooperates with controlling cam 86 to determine the position of lthe circuit breaker contacts as will hereinafter be described. The lower end 81 of the contact actuating arm 8| is notched and carries a pin 9| upon which a latch 92 is pivotally supported. The latch 92 is normally biased in a clockwise direction about the pin 9| by a small compression spring 93 contained in a recess of the arm 8|.

The'latch which controlsthe automatic tripping of the circuit breaker contacts is bevelled at 94 and contains a notch 95 in the lower surface thereof. The notch 95 is engageable with a pin 96 carried in ball bearings 91`that are secured in the contact operating arm 56.

In `relation with the lower smooth surface of the latch is a plunger |02 the motion of which is governed by the automatic tripping device |03. The automatic tripping device may comprise any current sensitive mechanism which will respond to predetermined currents flowing in the coil 61 to raise the plunger |02.

The plunger |02 may also be manuallyactuated by raising the knob |04.

Thus it may be seen that when the plunger |02 is raised as a result of an over current or manual displacement of theknob |04, the latch 92 pivots in a counterclockwise direction about its supporting pin 9| and releases the pin 96. Under these circumstances the contact carrying -arm 56 will be freed from the control of the actuating arm 8| and will move under the influence of tension springs 12 to the open circuit position.

The actuating arm 8| is normally biased by tension spring |05 towards counterclockwise rotation about the pivot 55. The spring |05 is secured by the pin |06 at one endto the frame 54, and at the other end by pin |01 to the extension 82 of the contact actuating arm.`

Under the influence of tension spring |05 it may be seen that the roller 85 will normally be biased into engagement with the curved surface of cam 86 and hence the rotation of actuating arm 8| about the pivot 55 will be governed by the rotation of the cam.

When the cam 86 is in the position illustrated in Figure 3, the roller 85 is in surface engagepoles.

It may be seen from Figure 4 that immediately subsequent to automatic tripping. the contact carrying arm 56 will move to its full .open positionfwhereas the contact actuating arm 6|J and its associated latch 92 will remain in a fixed posi- Before the breaker can be reclosed, the notch 95 in the latch inust engage the pin 96 on the contact carrying arm 56. The latch must be moved tc the right tc accomplish this. .Thus as' illustrated in Figure 5, clockwise rotation of the cam through an angle of approximately 90 from the position of Figure 4 to that of Figure 5 will cause the contact actuating arm 8| Ato rotate under the influence of spring |05 and move its lower end 81 to the right carrying with it the pin 9| and latch 92. This movement will cause the chamfered surface 94 of the latch 92 to ride over the pin 96 and thus permit reengagement of the pin 96 and the notch 95.

Continued clockwise rotation of the cam 86 from the position illustrated in Figure 5 will then cause clockwise rotation of the actuating arm 8| and corresponding movement of the latch 92 and the contact carrying arm about the shaft 55. This action will cause the reengagement of contacts 64 and 45 when the cam has rotated lto the position illustrated in Figure 3.

Accordingly, it may be seen in the above discussion that when the circuit breaker is in the position illustrated in Figure 3, automatic or.

As illustrated in Figure 1, a cam 86 is provided for each of the six circuit breaker poles and the six cams are suitably mounted upon a rotatable shaft which is driven by a motor |2|. The motor |2| is carried upon brackets secured to the channels 23 and 24 of the circuit breaker frame.

The motor |2| is preferably a compound motor and drives the cam shaft through a speed reducer and coupling |22. The cam shaft is sectionalized and comprises the two sections I 23 and |24 joined by a flexible coupling |25.

The individual shaft sectionsA |23 and |24 are supported upon the main circuit breaker frame ment with the highest portion of the cam and the contacts 64 and 45 are engaged as illustrated.

Should the latch 92 be released by the manual or automatic means provided, the contact carrying arm 56 will immediately be displaced to the position illustrated in Figure 4 under the influence of tension springs 12.

The movement of the contact carrying arm 56 about its pivot 55 under the influence of spring 12 is limited by a stop which is surfacedvwith a layer of resilient material ||2 such as rubber or the like. It may be seen also that lwhen the contact carrying arm 56 is permitted to ro` tate freely under the influence of spring 12, that movable contact 64 will be rotated in a clockwise manner about its pivot Aby the compression spring 62. This motion as previously mentioned is limited to the position where the extension 68 extension 63 of the contact carrying arm 56.

in bearings |26 which are carried upon transverse channel sections |21 as is more clearly illustrated in Figure 2. Thus the channel |21 is welded or otherwise secured to the main structural channels 23 and 24. A bearing member |3| having tapped holes |32 is secured to the channel |21 by suitable screws |33 and lock Washers |24.

A bore |35 in the bearing member |3| contains a loosely fitting bushing |36 of suitable bearing metal. This bushing .|36 is maintained within a bore 35 by a screw |31 which passes through a tapped hole |4| in the bearing member |3| and enters a relatively large openlongitudinal movement ,and so maintain the cams 86 in alignment with the rollers 85 of the individual poles.

4 :,soaess The sections |23 and I 24 of the cam shaft are coupled to each other by the loosely fitting cylindrical member |25 and by pins |46 and |41 which pass through holes |5| in the shaft sections and through corresponding holes |52 in the member |25. Cotter pins |53 prevent the accidental withdrawal of the pins |46 and |41. These pins are at right angles to each other and thus proper rotation of the shaft will be obtained even if the sections |23 and |24 are not in alignment.

'I'he sectionalized shaft is provided since it is quite possible that during shipment or during installation upon a permanent foundation the main structural frame comprising channels 23 and 24 will be warped. Each section of the shaft is thus supported in two bearings |26 which due to the fact that the bearing sleeves |36 are loosely positioned automatically align themselves to compensate for distortion of the frame.

For the particular bearing shown in Figure 2, namely, the extreme right hand bearing of Figure 1, an additional element is employed, namely a cam |54. This cam is non-rotatably secured to the shaft |24 by means of a key |55 nested in corresponding key ways in each member.

An enclosed limit switch |62 is secured to the channel member |21. The pivoted switch arm |56 carries in .its forked end a roller |51 biased against the surface of the cam |54. The enclosure contains contacts which are actuated when the cams 86 reach the positions of Figure 3 and Figure 5. The action of these contacts stops the motor.

The operating cams 86 for the individual circuit breaker poles illustrated in Figures 1, 2 and 2a are molded of high strength insulating material and comprise a hub |63 having a cylindrical bushing |64 embedded therein during the molding process.

The actuating cam itself is an irregularly shaped flange |65 extending from the molding. The bushing |64 contains a keyway |66 which, with a complementary keyway |61 in the shaft, cooperates with key |1| to prevent relative rotation. The cams 86 as illustrated in Figure l are spaced at equal intervals along the length of the shaft so that each cam surface' |65 aligns itself with the roller 85 of the individual poles.

The key |1| serves to position each cam 86 at its proper angular position on the shaft. The key |1| and cam are fixed against axial movement by a pair of steel set screws |12 which pass through tapped holes in the hub |63 of the cam 86 and the bushing |64. These set screws |12 are relatively short and hence do not extend to the outer surface of the hub |63. As illustrated in Figure 2, the metallic set screws |12 are covered by a pair of screws |13 of an insulating material.

The outer surface of each of the shaft sections between the various cams is covered with a sleeve of insulating material |14, and accordingly'the metal parts of the driving shaft are completely covered by insulating material in the vicinity of each of the circuit breaker poles.

Each of the cams 86 when mounted upon the shafts |23|24 are all secured thereto in the same relative angular position and hence it may be seen from Figures 1 and 3 that rotation of the shafts |23|24 by motor I2| will cause all of the circuit breaker contacts 64 to move simultaneously. Thus if the contacts are initially in the position illustrated in Figure 3, rotation of the cam in a clockwise manner will cause all circuit breaker contacts to open and if rotation is then continued, all circuit breaker contacts will close. Control means are provided to close all of the circuit breaker poles simultaneously or to open all of the poles simultaneously. The relays, which control the motor I2l, shaft |22|24 and cams 00, are housed within the enclosure |0| which is secured to the channel sections 23 and 24 at one end of the circuit breaker frame as il? lustrated in Figure 1.

The enclosure lli -contains all the necessary relays for circuit breaker operation and a reference is now made to the schematic diagram Figure 6 which illustrates the electrical control system for the circuit breaker.

In Figure 6 a single circuit breaker pole 2| is illustrated in schematic form. Thus the fixed contact 45 is shown in engagement with the separable contact 64 which is positioned upon the actuating member Il driven by the cam 80. The arm 8| is continuously biased by means of spring |05 towards the open circuit position and carries a switch operating lever |02 thereupon.

The actuating lever 8| and attached lever |02 (not shown in Figures l-5) control the operation of a switch having contacts. Six switches it-|88, one for each pole, are illustrated, and are connected in series for reasons which will hereinafter be explained.

The cam 86 positionedupcn the shaft |2l|24 is driven in a clockwise direction by motor armature |8| which is coupled thereto through a speed reducing mechanism.

The electric motor |2| is preferably a compound motor including a series fleld |82 and a shunt eld |83. The armature |8| is shunted by a resistor |84 to provide dynamic braking.

Although not illustrated in Figure 6, the six Cams 86 are all mounted upon the shaft |23|24 and rotate in unison. The limit switch control cam |54 is also diagrammatically illustrated in Figure 6 and as shown controls the movement of an arm |56 which is biased by spring |85 towards engagement with the cam surface.

The opposite end of arm |56 actuates the limit switch |82 which is supported as illustrated in Figure 2. 'I'he electrical control circuits of Figure 6 are energized from a suitable low voltage direct current source schematically illustrated as the control bus bars |88 and |81.

As illustrated in Figure 6, the circuit breaker poles are all in the closed circuit position and hence the contacts 64 and 45 are engaged and the switches I83|88 are closed. Also contacts 202 of the limit switch |52 are closed and contacts. 203 of the limit switch are opened. The position of contacts 202 and 203 is determined, of course, by the position of the cam follower |51 upon the cam |54.

When it is desired to trip the circuit breaker, the handle of the control switch 20| is moved to the left to close contacts 204. The closure of these contacts will complete a circuit from the control bus |86 through contacts 204 through the operating coll 205 of the tripping relay 206 and through closed contacts 202 to the control bus |81.

This will immediately energize the coil 205 and relay plunger 201 will rise as viewed in Figure 6 to close its contacts 2|| and 2|2. It may be seen that the closure of contacts 2|| will complete a circuit which through wires 2 i3, 2 4 and 2 5 short circuits contacts 204, and hence even though the control switch handle may be moved momentarily, the movement of plunger 201 will serve to maintain the coll 205 of the tripping relay in the energized state. This seals in the relay so that the tripping process may not be interrupted, once initiated.

The closure of contacts 2 I2 of the tripping relay 206 will complete a circuit from the bus bar |96 through wires 2|5, 2|4, 2|6, 2|1, through motor armature |9I, the series tleld |92, coil 22| of the v motor armature |9| the relay coil 22| is energizedv as previously mentioned and thus closes contacts 225. This places the shunt ileld |93 of the motor |2| directly across the control bus oars |96 and |91. Rotation in this manner will permit spring |05 to rotate lever 6| and thus separate all of the contacts 64 and 45, while simultaneously opening switch contacts |83 to |88. Also rotation of shaft |23|24 will open contacts 202 of limit switch |62 and close contacts 203 thereof.

I'he operation of the limit switch |62 occurs at the moment when the contacts are in the position illustrated in Figure 5, that is, when the contacts are in their fully separated position. At the instant that contacts 202 separate, the coil 205 of the tripping relay 206 is deenergized and thus the plunger 201 moves to the position indicated in Figure 6. This in turn causes the separation of contacts 2 |2 and the deenergization of the motor circuit including armature |9I, series coil |92, and shunt iield relay coil 22|.

In order to ensure a dynamic braking effect, the

relay 222 is arranged to open its contacts 225 somewhat after the motor circuit is deenergized by the opening of contacts 2I2. This time delay permits the shunt ileld |93 to remain energized ,when the amature |9| is deenergized. The shunt magnetic ileld will thus cause the generation of relatively large currents which when iiowing through resistor |94 will provide the braking action and effectively prevent drift of the cam shaft.

On the other hand, relay 222 is arranged so that when energized upon the closure of contacts 2 2, its contacts 225 close immediately. 'I'his permits the motor armature |9| to speed up at a relatively rapid rate.

The resistance |94 functions in addition to produce the dynamic braking effect to reduce the arcing which would normally occur at the contacts 2I2 as a result of the highly inductive circuit interrupted.

When the circuit interrupter is in the open circuit position, the contacts 203 of the limit switch |62 are closed and the contacts |83|39 are open. To close all of the circuit breaker poles simultaneously, the handle of the control switch 20| is moved to the right and accordingly contacts 23| close.

This action completes avcircuit from the con-y trol 'bus |96 through closed contacts 23| through a plurality of normally closed contacts 232 to a junction 233. From the junction 233 two circuits are completed. The ilrst circuit is through a coil 234 of the closing relay 235 to the control bus |91. The other circuit from the junction 233 is through coil 236 of the relay 235 through the now closed contacts 203 to the bus |91.

Hence it may be seen that upon the initiation of the closing operation, both coils 234 and 236 of the closing relay 235 are energized. The closing relay 235 comprises an E-shaped magnet 231, the outer legs of which carry the coils 234 and 236. A centrally pivotedmagnetic member 24| is arranged so that its ends are normally under the influence of magnetic iields produced by both of the coils 234 and 236.

Coil 236 is arranged to produce a stronger magnetic field than coil 234 and -hence since these coils are simultaneously energized, coil 236 will predominate and the magnetic member 24| will rotate in` a clockwise direction against the pole piece upon which the coil 236 is wound.

Attached to the magnetic member 24| is a contact operating arm 242 which when operated as previously described closes contacts 243, 244 and 245.

The closure of contacts 243, 244r and 245 will complete a circuit through wires 2|5, 246, closed contacts 243 and 245, and through contacts 232 to shortI circuit the closing contacts 23 Hence the momentary initiation of the closing operation will cause the sealing in of the closing contacts to complete the closing operation even if the operator releases the closing handle of switch 20|. The closure of contacts 243 and 244 .will complete an additional circuit from the control bus |96 through the motor armature |9| -and through the relay coil 22| to the control bus |91. Accordingly, the contacts 225 of relay 222 will close and the motor armature |9| will rotate to ,bring the contacts 64 and 45 of each pole from the j opening of contacts 203 will immediately deenergize the relay coil 236 and hence the magnetic member 24| will be drawn against the pole piece containing the coil 234 if this coil is still energized by the closure of contacts 23|.

If contacts 23| vare opened at this time, the magnetic member 24| will spring back to its normal central position as indicated in Figure 6. If these contacts are not opened, the magnetic member 24| will remain in contact with the pole upon which coil 234 is wound, even if coil 236 is subsequently reenergized.

With the contacts 23| closed, the coil 236 can be energized only-if all the poles close and then any one trips as a result of a fault. Therefore,

` itl may be seen that the provision of the coil 234 will prevent reclosing if contacts 23| are still closed and hence prevent repeated contact opening and closing on a faulty circuit.

Thus, after the breakers have closed and the contacts 203 are opened as illustrated in Figure 6, if the contacts 23| are still closed, an energizing circuit is completed for the winding 234 at the time when the energizing circuit for the winding 236 has been opened at contacts 203. Winding 234 therefore rotates the armature 24| in a counterclockwise direction to engage its pole face.

While the winding 234 is not suiciently strong to counteract the greater pull of winding 236 while the armature 24| is in its neutral position, itis sufficiently strong to prevent any energization 'of the winding 236 from pulling the armature 'fected without operating the switch 20| again to first the trip pomtion and then the re-closing position.

The separation of contacts 245 and 244 disconnects the motor |2| from the control bus although the shunt ileld |55 ls still energized by the time delay in relay 222. Accordingly, the dynamic braking effect previously mentioned will again be effective and the motor will stop in a relatively short time.

Thus the contacts will be maintained in the closed circuit position illustrated in Figure 3. The auxiliary switches |55|55 one of which is provided on each of the circuit breaker poles are closed when the associated contacts 54 and 45 are engaged and open immediately when these contacts are disengaged. Each of these switches are arranged in series in a circuit from the control bus |51 through wire 25| through the switches |55|55 and through coil 252 of a relay 255 to the control bus |55.

Thus when all of the main circuit breaker contacts are in the closed position, the relay coil 252 is energized and thus maintains contacts 254 open. Accordingly, should a fault occur in one of the individual circuit breaker poles illustrated in Figure 1 to cause the operation of its automatic current responsive device |55, its contacts 54 and 45 will separate and open one of the switches Ill-|55.

'This will deenergize relay coil 252 and the contacts 254 will close. The closure of contacts 254 will energize a circuit from control bus |55 through wire 255 through contacts 254 through wire 255l through normally closed contacts 251 of a switch which will be described in a later paragraph, through wire 2| 5 through tripping relay coil 255, through normally closed contacts 252 and through wire 224 to the control bus |51.

The completion of this circuit will cause the energization of tripping relay 255 and will cause the rotation of cam shaft ||24 to open all of the circuit breaker poles in the manner previously described.

It is to be noted that the circuit breaker pole which initiated this last mentioned operation will open under the influence of springs 12 and hence will open independently of the operation of the remainder of the circuit breaker poles. However, the immediately subsequent operation, that is, the rotation of -all cams 55 to open all of the circuit breaker poles will place all contacts including thosefof the automatically operated pole into the position indicated in Figure 5, which is that necessary for immediate reclosing, if desired.

'I'he switches |55|55 close as previously menwould tend to energize the tripping relay 255 to.

reopen the main contacts and 54.

In order to preclude this immediate tripping action, the contacts 251 have been included in the control switch 25| It may be seen from Figure 6 that when the closing operation is initiated by displacing the handle of control switch 25| to the right, the lever arm thereof opens contacts 251. Since contacts 251 are in the tripping relay circuit. the opening thereof will preclude the tripping of the circuit breaker poles as the main contacts of each pole engage.

Of course, an instant after the engagement of all main contacts 45 and 54, the coil 252 will be energized and contacts 254 ened. Thus, whenthecontrolhandleisreleasedandassumes theneutraiposition indicatedinl'iguree.thecon tncts2l1will close andplacethetrippingrelayin operative relation in the control circuit.

The disconnection of the tripping relay circuit by the opening of contacts 251 during circuit closure in no way affects the automatic operation or the various safety features included in the novel control circuit illustrated, even if the circuit breaker contacts are closed under fault conditions.

Thisisaresultoi'thefactthateachofthecircuit breaker poles has a current responsive device included thereupon and hence should the contacts be closed upon a fault the latch 52 will beraisedtoreleasethecontactcarryingarm which will accordingly open under the influence f of tension springs 12.

It is obvious that when the handle of the control relay 25| is allowed to assume its neutral p0- sition, contacts 251 will close, and if any of the circuit breaker poles have opened, will complete circuits to cause rotation of the cam shaft |25--- I24 to place all of the poles in the position indicated in Figure 5 for reclcsing.

If the multi-pole circuit breaker illustrated and its associated control system are employed for the protection of mercury arc rectifier anode circuits, then various other safety features may be incorporated.

In the operation of mercury arc rectiilers there are auxiliaries which are usually necessary for satisfactory performance. These auxiliaries include cooling water systems, ignition equipment, grid circuits for the control of current flow and the like. This apparatus may be provided with devices responsive to the various operating conditions to indicate that they are in proper worko ing order.

The contacts 252 connected in series in the closing circuit of the control system represent switches which are included in the aforementioned responsive devices and which will open their contacts lmder faulty conditions. Thus, for

example, if a pressure gauge indicates an improper working condition, one of the switches 252 will open. It may be seen in view of the above discussion, that if any one of the contacts 252 are open, an attempt to close the main contacts by moving the handle of control switch 25| to the right will fail inasmuch as contacts 252 are in the circuit leading to the coils of the relay 255.

In a similar manner the auxiliary apparatus used with mercury arc rectiilers may fail during operation. Switches 25| having contacts in par allel with contacts 254 represent switches on these auxiliaries which will close their contacts upon failure of the apparatus.

'l'he closure of any one of contacts 25| will affect the circuit breaker system in a manner similar to that previously described in connection with a closure of contacts 254, that is, a tripping of all of the circuit breaker poles.

Thus the circuit breaker control system illustrated provides novel means whereby failure of any of the rectifier auxiliaries will preclude closure of the main contacts or will cause immediate circuit interruption if the main contacts have been closed. If the circuit breaker poles are employed for protection of anode circuits of a rectifier, one of the contacts 25| may be an interlocking contact upon circuit interrupters in the cathode circuit or in the transformer circuits. Thus interruption of any of these circuit breakers would cause closure of one of the contacts 28| and consequent interruption of the anode circuits.

The control system herein illustrated may of course be applied to various installations, other than mercury arc rectifier circuits. 'I'hus the system illustrated may be applied to any polyphase circuit wherein it is desirable to permita single pole to open its contacts at high speed and prior to the interruption of the associated poles.

Similarly, the individual circuit breaker pole illustrated in Figures 1 through 5 and the mechanical means for closing and opening the circuit breaker pole may be applied to any particular circuit.

Thus, although I have presented many specific disclosures in the above speciiication, I prefer to be bound only by the scope of the appendedy claims.

, I claim:

1. In an electrical circuit comprising a plurality of conductors, va circuit breaker in series with each of said conductors, each of said breakers including a pair of separable contacts, means including cam means associated with each of said circuit breakers for actuating said contacts between open and closed circuit positions, means for driving said cam means in one direction to a r tacts vand in the same direction to a second predetermined position to close said contacts, vindividual automatic means associated with each of said circuit breakers for separating its contacts independently of the other circuit breakers in response to circuit conditions of said circuit breaker, and means operative when all of said contacts are in the closed position and the contacts of one of said circuit breakers separate to operate said same driving means to rotate said cams to said first predetermined position to separate all of said circuit breaker contacts.

2. In an electrical circuit comprising a plurality of conductors, a circuit breaker in series with each of said conductors, each of said breakers including a pair of separable contacts, means including cam means associated with each of said circuit breakers for actuating said contacts between open and closed circuit positions, said cam means being positioned upon and rotatable with a rotatable shaft, electromotive means for rotating said shaft in one direction to a first predetermined position to open said contacts and in the same direction to a second predetermined position to close said contacts, individual automatic means associated with each of said circuit breakers for separating its contacts independently of the other circuit breakers in rcsponse to circuit conditions of said circuit breaker, and means operative when all of the contacts are in the closed position and the contacts of one of said breakers separate to energize said electromotive means and rotate said shaft and cam means to said first predetermined position to separate all of said circuit breaker contacts.

3. In an electrical circuit comprising a plurality of conductors, a circuit breaker in series with each of said conductors, each of said breakers including a pair of separable contacts, means including cam means associated with each of said circuit breakers for actuating said contacts between open and closed circuit positions, said cam means being positioned upon and rotatable with a rotatable shaft, electromotive means for rotating said shaft in one direction to a iirst predetermined position to open said contact and in the same direction to a second predetermined position to close said contacts, individual automatic means associated with each of said circuit breakers for separating its contacts independently of the other circuit breakers in response to circuit conditions of said circuit breaker, and means operable when all of the contacts are in the closed position and the contacts of one of said breakers separate to energize said electromotive means and rotate said shaft and associated cam means to said first predetermined position to separate all of said circuit breaker contacts and means operative to deenergize said electromotive means when said cam means are in one of said predetermined positions.

4. In an electrical circuit comprising a plural--v ity of conductors, a circuit breaker in series with each of said conductors, each of said breakers including a pair of separable contacts, means including cam means associated with each of said circuit breakers for actuating, said contacts between open and closed circuit positions, said cam means being positioned upon and rotatable with a rotatable shaft, electromotive means for rotating said shaft in one direction to a rst predetermined position to open said contacts and in the same direction to a second predetermined position to close said contacts, individual automatic means associated with each of said circuit breakers for separating its contacts independently of the other circuitI breakers in kresponse to circuit conditions of said circuit breaker, means operative when all of the contacts are in the closed position and the contacts of one of said breakers separate to energize said electromotive means and rotate said shaft and associated cam means to said first predetermined position to separate all of said circuit breaker contacts, and means operative to deenergize said electromotive meansy when said cam means are in one of said predetermined positions,4 said last mentioned means comprising a switch and an additional cam operated by the rotation of said shaft.

5. In an electrical circuit comprising a plurality of conductors, a circuit breaker in series with each of said conductors, each of said breakers including a pair of separable contacts, means including cam means associated with each of said circuit brakers for actuating said contacts between open and closed circuit positions, said cani means being positioned upon and rotatable with a rotatable shaft, electromotive means-for rotating said shaft in one direction to a first predetermined position to open said contacts and in the same direction to a second predetermined position to close said contacts, individual automatic means associated with each of said circuit breakers for separating its contacts independently of the other circuit breakers in response to circuit conditions of said circuit breakers, means operative when all of the contacts are in the closed position and the contacts of one of said breakers separate, to energize said electromotive means and rotate said shaft and associated cam means to said first predetermined position to separate all of said circuit breaker contacts, and means operative to deenergize said electromotive means when said cams are in one of said predetermined lpositions, and brake said electromotive means to prevent overtravel of said cams.

6. In a multipole circuit interrupter, a framework, a plurality of individual single pole circuit breakers, for controlling individual circuits,

mounted upon said framework, each of said circuit breakers comprising a stationary contact, a complementary contact movable to a closed circuit position, and an open circuit position, a pivoted lever biased toward said open circuit position, said movable contact being supported upon said pivoted lever. a pivoted actuating member, a first arm on said member, a dlsengageable latch for connecting said first arm and said lever, a second arm on said member, a roller secured to said second arm, a cam, said roller being biased into engagement with said cam, said cam being rotatable to a first predetermined position to rotate said member and by means of said latch to move said lever and said movable Contact to said closed circuit position, said cam being rotatable to a second predetermined position to permit said roller biasing means to rotate said member and said latch, current responsive means operative in response to the individual circuit conditions of the associated circuit for disengaging said latch to permit said biased lever to move to said open circuit position, the initiation of said lever movement causing said cam to rotate from said first to said second predetermined position to reengage said latch.

7. In a multipole circuit interrupter, a framework, a plurality of individual single pole circuit breakers, for controlling individual circuits, mounted upon said framework, each of said circuit breakers comprising a stationary contact, a complementary contact movable to a closed circuit position and an open circuit position, a pivoted lever biased toward said open circuit position, said movable contact being supported upon said lever, a pivoted actuating member, a first arm on said member, a disengageable latch for connecting said first arm and said lever, a second arm on said member, a roller secured to said second arm, a cam, said roller being biased into engagement with said cam, said cam being rotatable to a first predetermined position to rotate said member and by means of said latch to move said lever and said movable contact to said closed circuit position, said cam being rotatable to a second predetermined position to permit said roller biasing means to rotate said member and said latch, current responsive means operative in response to the individual circuit conditions of the associated circuit for disengaging said latch to permit said biased lever to move to said open circuit position, and means responsive to the initiation of said lever movement for causing said cam to rotate from said first to said second predetennined position to reengage said latch, said means comprising a cam shaft mounted in said framework, and carrying the said cam for each circuit breaker, and also comprising an electric motor for rotating said cam shaft in one direction, all of said cams rotating in unison.

8. In a multipole circuit interrupter, a framework, a plurality of individual single pole circuit breakers, for controlling individual circuits, mounted upon said framework, each of said circuit breakers comprising a stationary contact, a complementary contact movable to a closed circuit position and an open circuit position, a pivoted lever biased toward said open circuit position, said movable contact being supported on said lever, a pivoted actuating member, a first arm on said member, a disengageable latch for connecting said first arm and said lever, a second arm on said member, a roller secured to said second arm, a cam, said roller being biased into engagement with said cam. said cam being rotatable to a first predetermined position to rotate said member and by means of said latch to move said lever and said movable contact to said closed circuit position, said cam being rotatable to a second predetermined position to permit said roller biasing means to rotate said member and said latch, current responsive means operative in response to the individual circuit conditions of the associated circuit for disengaging said latch to permit said biased lever to move to said open circuit position, av cam shaft mounted in said framework, said shaft carrying the said cam for each circuit breaker, an electric motor for rotating said cam shaft in one direction, all of said cams rotating in unison, said motor and cam shaft permitting the opening of all of said circuit breakers simultaneously and the closing of all of said circuit breakers simultaneously, and means controlled by the movement of said lever to its open circuit position causing the operation of said motor to rotate all cams to said second predetermined position.

9. In a. multipole circuit interrupr, a framework, a, plurality of individual single pole circuit breakers, for controlling individual circuits, mounted upon said framework, each of said circuit breakers comprising a stationary contact, a complementary contact movable to a closed circuit position and an open circuit position, a pivoted lever biased toward said-open circuit position, said movable contact being supported upon said lever, a pivoted actuating member, a first arm on said member, a disengageable latch for connecting said mst arm and said lever, a second arm on said member, a roller secured to said second arm, a cam, said roller being biased into engagement with said cam, said cam being rotatable to a first predetermined position to rotate said member and by means of said latch to move said lever and said movable contact to said closed circuit position, said cam being rotatable to a second predetermined position to permit said roller biasing means to rotate said member and said latch, current responsive means operative in response to the individual circuit conditions of the associated circuit for disengaging said latch to permit said biased lever to move to said open circuit position, a cam shaft mounted in said framework, said shaft carrying the said cam for each circuit breaker, an electric motor for rotating said cam shaft in one direction, all of said cams rotating in unison, said motor and cam shaft permitting the opening of all of said circuit breakers simultaneously and the closing of all of said circuit breakers simultaneously, and means controlled by the movement of said lever to its open circuit position for causing the operation of said motor to rotate all cams to said second predetermined position, said last mentioned cam rotation causing the movement of said members to open all of said circuit breakers and reengage released latches.

O'ITO JENSEN. 

